This lesson explores the role of potassium in the analysis of pigments, particularly in identifying manufacturing processes for lakes and inks. Potassium, though not a primary component in pigments, provides valuable information about the chemical processes used historically to create them.
Objectives
- Understand the significance of potassium in historical pigments and inks analysis.
- Identify potassium’s role in the manufacturing processes of lakes and inks.
- Analyze potassium peaks in XRF spectra and apply optimal detection techniques.
Materials
- High-density polyethylene (HDPE) sample.
- Samples of alum, stil de grain, indigo, and iron gall ink.
- stil de grain, indigo, and iron gall ink from PIGMENTS CHECKER.
- XRF spectrometer (configured for no-filter setup).
Lesson Plan
1. Introduction to Potassium in Pigments
- Discuss the historical use of potassium in manufacturing pigments, such as lakes and inks.
- Explain the role of alkaline solutions like potassium hydroxide and potassium-aluminum sulfate in colorants extraction and stabilization.
2. Potassium Detection in XRF Spectrometry
- Overview of potassium’s XRF characteristics, including K alpha and K beta peaks at 3.3 and 3.6 keV.
- Comparison of peak separations in potassium, sulfur, and chlorine to emphasize detection precision.
- Explain the no-filter setup and its importance in detecting trace potassium.
3. Analyzing Potassium in Samples
- Alum: Test and analyze its spectrum, noting the clear separation of potassium peaks.
- Stil de Grain: Discuss potassium’s role in extracting colorants from buckthorn berries and analyze its spectrum.
- Indigo: Highlight the use of potassium hydroxide in the manufacturing process and examine the spectrum.
- Iron Gall Ink: Explore the addition of potassium carbonate in stabilizing ink and analyze its spectrum for potassium content.
4. Application in Pigments and inks Analysis
- Discuss how potassium content can help distinguish different manufacturing processes.
- Emphasize its use in analyzing historical artifacts and quantifying potassium to identify specific techniques and materials.
